Cubic HfO2 doped with Y2O3 epitaxial films on GaAs (001) of enhanced dielectric constant
Journal
Applied Physics Letters
Journal Volume
90
Journal Issue
15
Date Issued
2007
Author(s)
Abstract
Nanometer thick cubic HfO2 doped with 19at.% Y2O3 (YDH) epitaxial films were grown on GaAs (001) using molecular beam epitaxy. Structural studies determined the epitaxial orientation relationships between the cubic YDH films and GaAs to be (001)GaAs∕∕(001)YDH and [100]GaAs∕∕[100]YDH. The YDH structure is strain relaxed with a lattice constant of 0.5122nm with a small mosaic spread of 0.023° and a twist angle of 2.9°. The YDH/GaAs interface is atomically abrupt without evidence of reacted interfacial layers. From C-V and I-V measurements a 7.7nm thick YDH film has an enhanced dielectric constant κ∼32, an equivalent oxide thickness of ∼0.94nm, an interfacial state density Dit∼7×1012cm−2eV−1, and a low leakage current density of 6×10−5A∕cm2 at 1V gate bias.
Type
journal article